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Magnetoresistance of atomic-sized contacts: an ab-initio study

Alexei Bagrets·Nikos Papanikolaou·Ingrid Mertig
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Abstract

The magnetoresistance (MR) effect in metallic atomic-sized contacts is studied theoretically by means of first-principle electronic structure calculations. We consider three-atom chains formed from Co, Cu, Si, and Al atoms suspended between semi-infinite Co leads. We employ the screened Korringa-Kohn-Rostoker Green's function method for the electronic structure calculation and evaluate the conductance in the ballistic limit using the Landauer approach. The conductance through the constrictions reflects the spin-splitting of the Co bands and causes high MR ratios, up to 50%. The influence of the structural changes on the conductance is studied by considering different geometrical arrangements of atoms forming the chains. Our results show that the conductance through s-like states is robust against geometrical changes, whereas the transmission is strongly influenced by the atomic arrangement if p or d states contribute to the current.

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Alexei Bagrets, Nikos Papanikolaou, Ingrid Mertig. 2004-05-17. Magnetoresistance of atomic-sized contacts: an ab-initio study. https://doi.org/10.1103/physrevb.70.064410

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